The solar cell industry has been developing for more than a half-century. Please refer to FIG. 1 and FIG. 2, which show a conventional solar cell structure 100 and manufacturing flow chart 200. The flow chart 200 includes the texturing process (step 21), diffusion process (step 22) and metallization process (step 23). A silicon wafer 110 is cleaned, and then a texturing process (step 21) and a diffusion process (step 22) are performed on the silicon wafer 110 to form a textured structure 140 with dopants. The conventional metallization process uses silver paste 120 as a material for the electrodes and fabricates the electrodes on the textured structure 140 using screen printing. The silicon wafer is put in a furnace to be heated at a temperature in a range of 700˜800° C. in order to enable the silicon powders in the silver paste to tightly combine with the silicon wafer.
Although it is a simple fabrication process to fabricate electrodes with silver paste using screen printing, the silicon wafer needs to be heated in the furnace at a high temperature in the process. The high temperature in the furnace causes dopants in the silicon wafer to diffuse again, which changes the doping concentration in the silicon wafer and also lowers the conversion efficiency of the solar cell.
In addition, the cost of the silicon substrate in the solar cell is a large portion of the overall cost of the solar cell, so the solar cell industry typically reduces the thickness of the silicon substrate to reduce the cost. The current thin solar cells have a thickness in a range of 120 μm˜150 μm. However, the thin solar cells are easy to crack during transferring to and soldering at the module manufacturer. Any cracked solar cells on the module need to be replaced manually which further increases the costs.
In order to overcome the drawbacks in the prior art, a method for manufacturing a solar cell is disclosed. The particular design in the present invention not only solves the problems described above, but also is easy to implement. Thus, the present invention has the utility for the industry.